Loft insulation

[zad3717]

Hi, i'm in a bit of a quandary...

I need to lift the boards and insulate my loft to a better standard, I have these options but unsure which is best

The joist are 100mm so not much room for thick rockwool. I can either cross lay more 100mm joist with an extra layer of 100mm rockwool then re-board. cost would be approx £19.45 per sqm

or do I use a super quilt, which is around £20 sqm.

If I use the super quilt can I leave some or all the rockwool that is there already and lay the quilt on top or do I have to remove this?

Thanks

 

[Notch7]

You need an air gap both sides of super quilt for it to perform correctly.

I’m unconvinced by it TBH.

have you considered this:

https://www.insulationsuperstore.co...ive-multifoil-insulation-90mm-549m2-pack.html

 

[cdbe]

100mm rockwool then re-board. cost would be approx £19.45 per sqm

Where you getting it from!

You'd be better using loft legs and 170mm on top of the existing. I'd buy quick if I were you, the 200mm above has increased in price since I looked at it yesterday!

 

[zad3717]

Where you getting it from!

View attachment 262866

You'd be better using loft legs and 170mm on top of the existing. I'd buy quick if I were you, the 200mm above has increased in price since I looked at it yesterday!

The per sqm price was including new boards, additional 4 x 2 timbers and the 100mm insulation all from Wickes.

Loft legs are too high I can only go up 100mm and at that I will be ducking in the loft

 

[zad3717]

You need an air gap both sides of super quilt for it to perform correctly.

I’m unconvinced by it TBH.

have you considered this:

https://www.insulationsuperstore.co...ive-multifoil-insulation-90mm-549m2-pack.html

I saw the air gap on the top so was unsure if I could lay on top of the rockwool already there.

And looking at the data on the hybrid stuff it would still need an air gap so wouldn't be able to lay over the top?

 

[cdbe]

The per sqm price was including new boards, additional 4 x 2 timbers and the 100mm insulation all from Wickes.

Loft legs are too high I can only go up 100mm and at that I will be ducking in the loft

Price up some 100mm celotex, you can lay directly onto existing boards or even the joists, only need a bit of thin plywood or hardboard on top to form a usable loft floor.

 

[foxhole]

The per sqm price was including new boards, additional 4 x 2 timbers and the 100mm insulation all from Wickes.

Loft legs are too high I can only go up 100mm and at that I will be ducking in the loft

Many lofts are not head height , not usually a consideration unless you live up there.